Anti-stalling gasoline composition



United States Patent 2,987,385 ANTI-STALLING GASOLINE COMPOSITION Richard J. De Gray, Shaker Heights, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Filed Feb. 16, 1959, Ser. No. 793,252 8 Claims. (Cl. 44-66) This invention relates to a motor fuel composition adapted to minimize carburetor icing in automotive engines in cool, moist atmospheric conditions. In particular, this invention relates to a hydrocarbon fuel which alleviates carburetor icing, consisting essentially of a commercial gasoline and small percentages of a phosphorus com pound and a reaction mixture of commercial lecithin and a N-aliphatic hydrocarbon substituted trimethylene diarnine of the following general formula:

wherein R is an aliphatic hydrocarbon group containing 8 to 20 carbon atoms. By the above definition, it is intended that the hydrocarbon fuel may also contain conventional amounts of additives commonly employed for a commercial motor fuel, such as tetraethyl lead, oxidation inhibitors, surface ignition and rumble suppressants, gum inhibitors, solvent oil, dyes, and the like.

For years the average motorist has been annoyed with operational difficulties of automobile engines under idling conditions characterized by frequent stalling when operating the engine in weather conditions where the combination of high humidity and temperatures lower than 60 F. are present. In recent years this annoyance has been aggravated by various automatic mechanical innovations to modern engines, such as automatic transmissions and automatic chokes, which prevent the driver from manually controlling the engine during the warm-up period when icing conditions are most critical, together with the need of these modern engines for more volatile motor fuels.

Furthermore, when the engine of a car with an automatic transmission stalls, the motorist is forced to move the gear selector into neutral to restart the engine and then return the gear selector to the desired drive, all of which is time consuming and troublesome, particularly if the engine stall should occur in urban traffic. Consequently, the complaint of such stalling difficulty is quite prevalent today, being far more troublesome to the motorist presently than in the past, and seems to be experienced in all types of cars using all types of carburetors and utilizing the present day commercial grades of gasoline.

A thorough study of this problem indicates that the cause of this stalling effect is due to the formation of ice in the carburetor of the engine. Vaporization of the gasoline in the carburetor requires heat from the incoming air and from nearby carburetor parts. Therefore, on cool and humid days as the air is cooled by the vaporization of gasoline, its ability to hold moisture is lessened and, if the dew point is exceeded, the excess water will drop out of the air and condense on the surrounding carburetor parts which have been reduced in temperature below the freezing point of water. Ice formation on the throttle plate and walls of the carburetor results, and after a short while the ice build-up restricts the narrow air openings in ice the carburetor, causing the engine to stall. This condition is most likely to occur during engine warm-up when the engine is below its normal operating temperature but is also commonly experienced during other periods of light load operation, such as when the engine is idling.

It is therefore the object of the motor fuel composition of this invention to alleviate the operational difliculties previously described in a gasoline engine caused by carburetor icing.

In accordance with this invention, it has been found that a gasoline-soluble phosphorus compound and a reaction product of lecithin and a N-alphatic hydrocarbon substituted trimethylene diamine exhibit a coaction when used together in a gasoline, demonstrating a synergistic improvement in the fuel with respect to anti-icing. This coaction between the two materials is particularly surprising in view of the fact that neither of the materials, when used in gasoline independently, offers any appreciable advantage with respect to anti-icing performance, and certainly the elfect demonstrated by the coaction is significantly higher than would be expected from the two mate'- rials independently in gasolines.

THE PHOSPHORUS ADDITIVE wherein R is an aryl group, preferably a benzene or alkyl substituted benzene containing up to 9 carbon atoms, and R and R are'aryl groups the same or different than R falling within the definition of R or alkyl groups selected from C to C alkyl groups. Illustrative compounds of this class of phosphate ester compounds are tritolyl phosphate, dimethyl xylyl phosphate, tolyl diphenyl phosphate, di-tolyl phenyl phosphate, ethyl di-tolyl phosphate, and di-isopropyl phenyl phosphate.

(b) Gasoline-soluble phosphites of the following empirical formula: P(OX) in which X represents an alkyl group selected from the group of C to C alkyl groups but which may or may not be the same for all three positions of X in the molecule. Illustrative compounds of this class of phosphites are tri-ethyl phosphite, tri-octyl phosphite, di-ethyl amyl phosphite, di-isopropyl ethyl phosphite, tri-butyl phosphite, and dimethyl ethyl phosphite.

(c) Tri-alkyl phosphine compounds of the following empirical formula: Y P, in which Y represents an alkyl group which need not be the same for all three positions of Y in the molecule. The alkyl groups represented by Y may be any C to C alkyl groups, primary and secondary 0., alkyl groups, and primary C alkyl groups. Of these compounds, the preferred species are those in which at least two of the alkyl groups are in the range from C to C inclusive, with the third alkyl group being in the range from C to C as defined above. This preferred group thus includes, in addition to the compounds having the same alkyl group at all three positions,

et comp u d as clisth l m thyl restraint slis h propyl phosphine, diethyl isopropyl phosphine, the diethyl butyl phosphines, and the diethyl amyl phosphines.

It is preferred to express the amount of the phosphorus compound to be added as the percent by weight of elemental phosphorus that is supplied to the fuel. It has been found in accordance with the present invention that the phosphorus compounds disclosed as suitable for the fuel of the invention may -be added to the gasoline in amounts to provide from 0.0007% to 0.0042%, but preferably from 0.00105 to 0.002l% by weight elemental phosphorus.

LECI THIN-DIAMINE ADDITIVE (a) The lecizhin.It is desired that the lecithin used to prepare the desired lecithin-diamine reaction mixture be a quality grade, commercially filtered lecithin, preferably having a very low level of benzene insoluble materials. It may be obtained by centrifugal separation from a soybean oil that is free of foreign material and that has been filtered in the miscella stage and has been further clarified by a second filtration using diatomaceous earth in order to reduce the benzene insoluble content of said oil to a very low level. The precipitated lecithin product may then dried to a toluene moisture value of less than 1.0% and filtered, if necessary, so that the benzene insoluble value does not exceed 0.2% by weight. w

(b) The diamine.The N-aliphatic hydrocarbon substituted trimethylene diamines used to prepare this reaction mixture are relatively strong organic bases containing primary and secondary amine groupings having the following general formula:

wherein R represents an aliphatic hydrocarbon, preferably an alkyl or alkylene group, derived from a fatty acid having from 8 to 20 carbon atoms. These compounds may be prepared by reacting an amine of a fatty acid or amines of mixed fatty acids with acrylonitrile and then subsequently hydrogenating the available nitrile group to obtain the desired diamine. Since these materials are well known to the art and are commercially available, no further discussion of their preparation will be given here.

R-" in the foregoing general formula is usually derived from a commercial grade fatty acid, such as oleic acid, which may include small amounts of other acids, or from a mixture of fatty acids obtained by the hydrolysis of fats and oils such as tallow, soybean oil, cottonseed oil, coconut oil, tall oil, etc.

(c) The reaction mixture.-The lecithin-diamine reaction mixtures for the fuel of the present invention may be prepared by mixing from 10 to 80 parts of lecithin with from 90 to 20 parts of a diamine or a mixture of diamiues from the class previously described at a temperature and for a time so that the reaction mixture reaches substantial equilibrium. No definite chemical configuration or identi' "by infrared spectroscopy.

It may be postulated that the amide linkages, as determined by the infrared analysis, are due to the aminolysis of the phosphatides and/ or glycerides present in the lecithin since the moisture content of the reaction mixture would indicate that no water of formation occurred during the reaction, as would be expected if the amide linkage were a result of the neutralization of the free fatty acids which are always present in commercial lecithin.

Detailed study of the infrared analysis of the reaction mixture clearly reveals that a characteristic band for the pure diamine compound is absent, indicating that the diamine is in combined form or otherwise converted in some form in the reaction.

"verses The mixing temperature for the reaction is not critical. The reactants may be brought together at ambient temperature. Since lecithin is quite viscous, it will be desirable to maintain the mixing temperature above approximately 40 F. for handling ease. Lecithin is also subject to decomposition at high temperatures, and therefore it is desirable not to use temperatures in mixing in excess of 400 F. A desired mixing temperature range for the reaction is from F. to F.

The time of mixing will vary considerably depending upon the mixing temperatures employed; the higher the temperature, the shorter the time, and vice versa. The time for reaction may be as short as a few minutes at the upper temperature, but a time of from 15 minutes to 20 hours will generally be preferred, particularly when the reaction is carried out within the preferred temperature range previously set forth. For any given temperature the time should be at least as long as required to reach equilibrium as indicated by analysis. Longer times are not harmful if below the decomposition temperature of lecithin. More detailed information as to the nature and preparation of these reaction mixturesof lecithin and a diamine may be obtained from co-pending application Serial No. 793,268, filed on even date with this application, in the names of Donald E. Sincroft and Endre F. Sipos, and the description of application Serial No. 793,- 268 is incorporated herein by reference to the extent as may be required for a clear and complete understanding of said reaction mixtures.

The following is a description of a typical preparation of a lecithin-diamine reaction mixture useful for purposes of the present invention.

LECITHIN-DIAMINE ADDITIVB A To 80 lbs. of lecithin obtained from soybean oil, said lecithin having a moisture content of 0.80%, a bQnZene insolubles value of 0.15%, and an acetone insolubles value of 70%, was added 12% by weight a mineral oil a saturated aliphatic hydrocarbon'having an approximate molecular weight of 150. The oil merely reduces viscosity and does not take part in the reaction. The viscosity of the resulting mixture was in a range of 5,000 centipoises and the acetone insolubles was decreased through dilution to a value of 63.5%. At this stage, 20 lbs. of a N-aliphatic hydrocarbon substituted trimethylene diamine, in which the aliphatic hydrocarbon group is derived from the mixed fatty acids obtained by the hydrolysis of coconut oil, was added to the lecithin solution in conventional mixing equipment at a temperature of 150 F., and the reaction was continued at this temperature for a period of sixteen hours, by which time the reaction mixture reached substantial equilibrium.

The reaction mixture suitable for the fuel of the present invention possesses distinct and unique properties from any known commercial lecithin or modified lecithin. In Table I below the physical properties of the lecithindiamine reaction mixture prepared from the foregoing preparation is compared with the properties of the commercial lecithin used as a reactant in the preparation.

Lecithin base diluted with 12% by weight of mineral oil. Following the same procedure, lecithin-diamine additives identified as B through I were made with various diamines and proportions as indicated in the following table:

Table 11 Lecithin- Diamine Additive "R in the General Formula for Parts the Diamine Derived fromby wt.

Lecithin Parts by wt. Diamine Mixed acids from coconut Oil Oleic acid d Equal parts oleic and mixed acids from coconut oil.

For purposes of the present invention, these reaction mixtures may be added to gasoline in a range of from 0.0025 to 0.02% by weight, but preferably in the range of from 0.005 to 0.01% by weight. Amounts in excess of 0.01% do not give results significantly better than 0.01% but do not interfere with the synergy. It is, of course, uneconomic to use more than necessary.

Within the ranges described heretofore, the results are not critical and any can be used to give the anti-icing efiect.

THE ANTI-ICING ADDITIVE SYSTEM A more complete understanding of the anti-icing synergy that is obtained by the use of the fuel of the invention containing a combination of a phosphorus compound and a lecithin-diamine reaction mixture of the types described hereinbetore may be appreciated from the following results obtained in laboratory testing apparatus constructed to simulate the stop-and-go type of engine operation normally experienced by the motorist during the engine warm-up period, together with the atmospheric conditions which give rise to carburetor icing.

The test was conducted in a 1955 Plymouth V-8 engine equipped with a two-barrel carburetor. Carburetor air was supplied at a constant rate of 70 cu. ft. per minute by a specially designed air conditioner controlled at 45 F. and 85% relative humidity, which are temperature and humidity conditions frequently encountered and conducive to carburetor icing. All test conditions for each of the runs were the same except for the gasoline.

The test consisted of running five cycles on each fuel where in each cycle the engine was operated at 2200 r.p.m. for 10 seconds and then die-accelerated normally to an idle at 600 r.p.m. for a maximum of 30 seconds. Performance of the engine was observed during each idle period, and a numerical rating based on the degree of rough idling and engine stalls was assigned so that each fuel received a merit rating on a scale ranging from 100 to 0. By this scheme, an engine operating with a smooth idle over the idle periods of every test cycle would receive a rating of 100 and an engine which stalled in less than 8 seconds in the idle period of every test cycle would receive a rating of 0. The base fuel used had the following composition and specifications:

e 1 ASTM distillation, F.:

I.B.P. 10% 111 30 141 50 186 70 243 310 -E.P. 366 ;F-1 octane No. 100.3 F-2 octane No. 90.0

The results of this test are presented in Table III below:

Table III ANTI-ICING MERIT RATING Fuel Rating Base Only Phosphates:

Base+0.005% lecithin-diamine Additive A Base+0.0021% P as dimethyl xylyl phosphate Base+0.005% leeithin-diamiue Additive A+0 021% P as dimethyl xylyl phosphate Base+0.005% lecithin-diamine Additive 0.- Base+0.002i% P as tri-tolyl phosphate Based-0.005% lecithin-diam'me Additive C+0.002l% P as tri-tolyl phosphate Base+0.005% lecithin-diamine Additive A Base+0.0021% P as tolyl diphenyl phosphate Based-0.005% lecithin-diarnine Additive A+0 0021% P as tolyl diphenyl phosphate Based-0.005% lecithin-diamine Additive F Base+0. Based-0.005% lecithin-diamine Additive F+0iO02l% P as dimethyl xylyl phosphate Phosphites:

Based-0.005% lecithiu-diamine Additive G Base+0.002i% P as tri-ethyl phosphite Base+0.005% lecithin-diamine Additive G+0 002i% P as triethyl phosphite Base+0.005% lecithin-diamiue Additive H Base-i-(LOOZUZ, P as tri-octyl phosphite Based-0.005% lecithin-diamine Additive H+0.0021% P as tri-octyl phosphite Base+0.005% lecithin-diamine Additive J Base+0.002l% P as tri-octyl phosphite Base+0.005% lecithin-diamine Additive J+0.0021% P as tri-octyl oho n Phosphine:

Base+0.005% leoithin-diamine Additive 13.- Base-H).002l% P as tri-n-butyl phosphine.-- Based-0.005% lecithin-diamine Additive B+0 021% P as tn-n-butyl phosphine It will be obvious from the results in Table III that the effect toward anti-icing merit rating demonstrated by the coaction of the phosphorus compound and the lecithin-diamine additive is significantly higher than would be expected from the two materials independently in gasoline. For example, the coaction between dimethyl xylyl phosphate and the lecithin-diamine additive A improves the merit rating of the base fuel from 62 to 84, or an increase of 22 units as compared to an increase of 4 units which is the improvement obtained by summing the independent effects of these compounds in gasoline.

Similarly, the coaction between any combinationof phosphorus compound and lecithin-diamine additive shown in Table III produces an unexpected improvement toward anti-icing merit rating.

The data from Table III, furthermore, shows that the synergy toward anti-stalling for the additive system of the present invention may be demonstrated for a large number of phosphorus compounds when these compounds are present in the fuel, which also contains small amounts of a lecithin-diamine reaction product of the class described hereinbefore.

' It will be seen from the results reported in Table IV below, obtained from further testing of additive systems for the present invention with the same base fuel, that the coaction between a phosphorus compound and a lecithin-diamine reaction mixture may be demonstrated as the concentration of the phosphorus compound or as the concentration of the lecithin-diarnine reaction mixture is varied in the fuel.

Table IV:.

-ANII-ICING MERIT RATING Fuel BaseOnlyv a r t $9+01 l ithin-Gimm Ad iti eQ-P-V Base+0.0042% P as tri-tolyl phosphate Base+0.005% -lecithin-diamine 'Additive G+0.0042% P as tri t ol vl nlmsnh ate u A g r Base+0.005% le'ithimdiarhine Additive O -I 63 Base+0.0007%-P as tri-tolyl-phosphate Based-0.005% leoithin-diamine Additive 0+0 0 las tri-tolyl phosphate." Base+0.0025% lecithiu-di in Base+0.0021% P as dimethyl xylyl phosphate Base+0.0025% lecithiu-diamiue Additive C+0.0021% P as dimethyl xylyl phosphate Base+0.01% lecithiu-diamine Additive C Basel-0.002175 P as dimethyl xylyl phosphate Base+0.01% lecithin-diarnine Additive 0+0 0021% P as dim ethyl xylyl phosphate Base+0.005% leoithiu-diamine Add 0 Base-k0.0042% P as tri-tolyl phosphate .Base+0.005% lecithin-diamine Additive C+0.0042% P as tri-tolyl phosphate -Base+0.005% lecithin-diamine Additive 0.- 63 Base+0.0007% P as tri-tolyl phosphate Base+0.005% lecithiu-diamine Additive 0+ 007% P as tri-tolyl phos hate Base+0.0025% lecithiu-diarnine Additive E Base-P01102170 P as dimethyl xylyl phosphate .Base+0.0025% leoithin-diamine Additive E+0.0021% P as dimethyl xylyl phosphate Base+0.01% lecithin-diamine Additive E Based-0.0021951 as dimethyl xylyl hosphate.

Base+0.01% lecithin-diamine Additive E+ 021% P as dimethyl xylyl phosphate It will, of course, be obvious from the foregoing that the coaction for any other phosphorus compound or lecithin-diamine reaction mixture can be optimized in a particular hydrocarbon fuel with the careful balancing of the other component of this two-component additive system, together with the adjustment of the concentration of both additives by means of routine laboratory investigation, such as will occur to those skilled in the art. I claim: 1. An anti-stalling gasoline consisting essentially of a gasoline base stock, a reaction mixture resulting from the reaction of from to 80 parts of lecithin with 90 to parts of a N-aliphatic hydrocarbon substituted trime thylone diamine of the general formula:

wherein R is an aliphatic hydrocarbon group containing 8 to 20 carbon atoms in an amount of from 0.0025 to 0.02% by weight of said gasoline; and a phosphorus compound selected from the group consisting of (1) a phosphate of the following general formula:

-'sisting of C to C alkyl groups, primary and secondary Q alkyl groups, and primary C alkyl group, in an amount suflicient to supply from 0.0007 to 0.0042% by weight elemental phosphorus to said gasoline.

2. An anti-stalling gasoline consisting essentially of a gasoline base stock, an amount of dimethyl xylyl phosphate s'ufiicient to supply from 0.00105 to 0.0021% by weight elemental phosphorous to said gasoline and from -0.005 to 0.01% byweight of said gasoline a reaction mixture resulting from mixing together from 10 to 80 parts of lecithin with 9.010 -20 part at a -alipbati; .hy' drocarbon substituted trimethylene diamine of the goth eral formula:

HHH

wherein R is an aliphatic hydrocarbon group containing 8 to 20 carbon atoms.

4. anti-stalling gasoline consisting essentially of a gasoline base stock, an amount of tolyl diphenyl phos phate sutficient to supply from 0.00105 to 0.0021% by weightelemental' phosphorus to said gasoline and from 0.005 to 0.01% by weight of said gasoline a reaction mixture resulting from mixing together from 10 to parts of lecithin with to 20 parts of a N-aliphatic hydrocarbon substituted trimethylene diamine of the general formula:

r r r lllll HHHHH wher i R is n a ipha c y bon g up c ntaini 8 to 20 carbon atoms. 0

5. An ntitalling ga in on is g ess n ia y of a asoline base stock, an amount of tri-ethyl phosphite suflicient to supply from 0.00105 to 0.0021% by weight elemental phosphorus to said gasoline and from 0.005 to 0.01% by weight of said gasoline a reaction mixture resulting from mixing together from 10 to 80 parts of lecithin with 90 to 20 parts of a N-aliphatic hydrocarbon substituted trimethylene diamine of the general formula:

wherein R is an aliphatic hydrocarbon group containing 8 to 20 carbon atoms.

6. An anti-stalling gasoline consisting essentially of a gasoline base stock, an amount of tri-n-octyl phosphite suificient to supply from 0.00105 to 0.0021% by weight elemental phosphorus to said gasoline and from 0.005 to 0.01% by weight of said gasoline a reaction mixture resulting from mixing together from 10 to 80 parts of lecithin with 90 to 20 parts of a N-aliphatie hydrocarbon substituted trimethylene diamine of the general formula:

llll HHHHH wherein R is an aliphatic hydrocarbon group containing 8 to 20 carbon atoms.

7. An anti-stalling gasoline consisting essentially of a gasoline base stock, an amount of tri-n-butyl phosphine sufiicient to supply from 0.00105 to 0.0021% by weight elemental phosphorus to said gasoline and from 0.005 to 0.01% by weight of said gasoline a reaction mixture resulting from mixing together from 10 to 80 parts of leci- 9 thin with 90 to 20 parts of a N-aliphatic hydrocarbon substituted trimethylene diamine of the general formula:

H H H wherein R is an aliphatic hydrocarbon group containing 8 to 20 carbon atoms.

8. An anti-stalling gasoline additive consisting essentially of from 25 to 200 parts of a reaction mixture resulting from the reaction of 10 to 80 parts of lecithin with 90 to 20 parts of a N-aliphatic hydrocarbon substituted trimethylene diamine of the general formula:

Illll HHHHH wherein R is a mononuclear aryl group and R and R are selected from the group consisting of mononuclear aryl groups that are the same as R mononuclear aryl groups that are different than R and C to C alkyl groups; (2) a phosphite of the following general formula: P(OX) in which the Xs are selected from the group consisting of C to C alkyl groups; and (3) a trialkyl phosphine of the following general formula: Y P in which the Ys are selected from the group consisting of C to C alkyl groups, primary and secondary C alkyl groups, and primary C alkyl group.

References Cited in the tile of this patent UNITED STATES PATENTS 2,080,299 Benning et al. May 11, 1937 2,274,291 Clayton et al. Feb. 24, 1942 2,295,179 Loane Sept. 8, 1942 2,851,343 Cantrell et al. Sept. 9, 1958 2,863,742 Cantrell et a1. Dec. 9, 1958 2,891,850 Cosgrove et a1. June 23, 1959 FOREIGN PATENTS 776,314 Great Britain June 5, 1957 OTHER REFERENCES Petroleum Refining With Chemicals, Kalichevsky and Kobe, 1956, Elsevier Pub. 00., page 480. 

1. AN ANTI-STALLING GASOLINE CONSISTING ESSENTIALLY OF A GASOLINE BASE STOCK, A REACTION MIXTURE RESULTING FROM THE REACTION OF FROM 10 TO 80 PARTS OF LECITHIN WITH 90 TO 20 PARTS OF A N-ALIPHATIC HYDROCARBON SUBSTITUTED TRIMETHYLENE DIAMINE OF THE GENERAL FORMULA: 